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Beam Conditioning for FELs: Consequences and Methods

Description: The consequences of beam conditioning in four example cases (VISA, a Soft X-Ray FEL, LCLS and a ''Greenfield'' FEL) are examined. It is shown that in emittance limited cases, proper conditioning reduces sensitivity to the transverse emittance, and allows stronger focusing in the undulator. Simulations show higher saturation power, with gain lengths reduced up to a factor of two. The beam dynamics in a general conditioning system are studied, with ''matching conditions'' derived for achieving conditioning without growth in effective emittance. Various conditioners are considered, and expressions derived for the amount of conditioning provided in each case when the matching conditions are satisfied. We discuss the prospects for conditioners based on laser and plasma systems.
Date: October 9, 2003
Creator: Wolski, Andrzej; Penn, Gregory; Sessler, Andrew & Wurtele, Jonathan
Partner: UNT Libraries Government Documents Department

Spectral measurements of the second harmonic of the SASE FEL radiation at APS.

Description: We present the z-dependent spectral measurement results for the second harmonic of the SASE FEL radiation before and after saturation. The measurements were performed at the Advanced Photon Source FEL with the fundamental wavelength of 530 nm. The spectral properties of the second harmonic are compared with those of the fundamental and with the theoretical expectations.
Date: October 3, 2002
Creator: Sajaev, V. & Huang, Z.
Partner: UNT Libraries Government Documents Department

Pressure and fluid saturation prediction in a multicomponent reservoir, using combined seismic and electromagnetic imaging

Description: This paper presents a method for combining seismic and electromagnetic measurements to predict changes in water saturation, pressure, and CO{sub 2} gas/oil ratio in a reservoir undergoing CO{sub 2} flood. Crosswell seismic and electromagnetic data sets taken before and during CO{sub 2} flooding of an oil reservoir are inverted to produce crosswell images of the change in compressional velocity, shear velocity, and electrical conductivity during a CO{sub 2} injection pilot study. A rock properties model is developed using measured log porosity, fluid saturations, pressure, temperature, bulk density, sonic velocity, and electrical conductivity. The parameters of the rock properties model are found by an L1-norm simplex minimization of predicted and observed differences in compressional velocity and density. A separate minimization, using Archie's law, provides parameters for modeling the relations between water saturation, porosity, and the electrical conductivity. The rock-properties model is used to generate relationships between changes in geophysical parameters and changes in reservoir parameters. Electrical conductivity changes are directly mapped to changes in water saturation; estimated changes in water saturation are used along with the observed changes in shear wave velocity to predict changes in reservoir pressure. The estimation of the spatial extent and amount of CO{sub 2} relies on first removing the effects of the water saturation and pressure changes from the observed compressional velocity changes, producing a residual compressional velocity change. This velocity change is then interpreted in terms of increases in the CO{sub 2}/oil ratio. Resulting images of the CO{sub 2}/oil ratio show CO{sub 2}-rich zones that are well correlated to the location of injection perforations, with the size of these zones also correlating to the amount of injected CO{sub 2}. The images produced by this process are better correlated to the location and amount of injected CO{sub 2} than are any of the individual images of ...
Date: 2002-10~
Creator: Hoversten, G. M.; Gritto, Roland; Washbourne, John & Daley, Tom
Partner: UNT Libraries Government Documents Department

Electrical resistivity monitoring of the single heater test in Yucca Mountain

Description: Of the several thermal, mechanical and hydrological measurements being used to monitor the rockmass response in the Single Heater Test, electrical resistance tomography (ERT) is being used to monitor the movement of liquid water with a special interest in the movement of condensate out of the system. Images of resistivity change were calculated using data collected before, during and after the heating episode. This report will concentrate on the results obtained after heating ceased; previous reports discuss the results obtained during the heating phase. The changes recovered show a region of increasing resistivity approximately centered around the heater as the rock mass cooled. The size of this region grows with time and the resistivity increases become stronger. The increases in resistivity are caused by both temperature and saturation changes. The Waxman Smits model has been used to calculate rock saturation after accounting for temperature effects. The saturation estimates suggest that during the heating phase, a region of drying forms around the heater. During the cooling phase, the dry region has remained relatively stable. Wetter rock regions which developed below the heater during the heating phase, are slowly becoming smaller in size during the cooling phase. The last set of images indicate that some rewetting of the dry zone may be occurring. The accuracy of the saturation estimates depends on several factors that are only partly understood.
Date: October 1, 1997
Creator: Ramirez, A.
Partner: UNT Libraries Government Documents Department

Temperature limits based on the saturation temperature in Hanford waste storage tanks

Description: This report calculates limits on the measured temperature readings to limit the occurrence of saturation temperatures in Hanford waste storage tanks. The results in this report show that the temperature reported by a thermocouple tree in a double-shell tank can be significantly below the maximum waste temperature and that provisions should be made for that offset in any tank temperature monitoring program. The results for single-shell tanks show that some tanks may be at or above the saturation temperature.
Date: October 14, 1996
Creator: Bander, T.J.
Partner: UNT Libraries Government Documents Department

Organic Dye Effects on DNAPL Entry Pressure in Water Saturated Porous Media

Description: One of three diazo dyes with the same fundamental structure have been used in most studies of DNAPL behavior in porous media to stain the NAPL: Sudan III, Sudan IV, or Oil-Red-O. The dyes are generally implicitly assumed to not influence DNAPL behavior. That assumption was tested using simple entry pressure experiments.
Date: October 2, 2001
Creator: Iversen, G.M.
Partner: UNT Libraries Government Documents Department


Description: The Fiddler Creek field is in Weston County, Wyoming, and was discovered in 1948. Secondary waterflooding recovery was started in 1955 and terminated in the mid-1980s with a fieldwide recovery of approximately 40%. The West Fiddler Creek Unit, the focus of this project, had a lower recovery and therefore has the most remaining oil. Before the project this unit was producing approximately 85 bbl of oil per day from 20 pumping wells and 17 swab wells. The recovery process planned for this project involved adapting two independent processes, the injection of polymer as a channel blocker or as a deep-penetrating permeability modifier, and the stabilization of clays and reduction of the residual oil saturation in the near-wellbore area around the injection wells. Clay stabilization was not conducted because long-term fresh water injection had not severely reduced the injectivity. It was determined that future polymer injection would not be affected by the clay. For the project, two adjoining project patterns were selected on the basis of prior reservoir studies and current well availability and production. The primary injection well of Pattern 1 was treated with a small batch of MARCIT gel to create channel blocking. The long-term test was designed for three phases: (1) 77 days of injection of a 300-mg/l cationic polyacrylamide, (2) 15 days of injection of a 300-mg/l anionic polymer to ensure injectivity of the polymer, and (3) 369 days of injection of the 300-mg/l anionic polymer and a 30:1 mix of the crosslinker. Phases 1 and 2 were conducted as planned. Phase 3 was started in late March 1999 and terminated in May 2001. In this phase, a crosslinker was added with the anionic polymer. Total injection for Phase 3 was 709,064 bbl. To maintain the desired injection rate, the injection pressure was slowly increased from 1,400 ...
Date: October 31, 2001
Creator: Johnson, Lyle A., Jr.
Partner: UNT Libraries Government Documents Department

Unsaturated Groundwater Flow Beneath Upper Mortandad Canyon, Los Alamos, New Mexico

Description: Mortandad Canyon is a discharge site for treated industrial effluents containing radionuclides and other chemicals at Los Alamos National Laboratory, New Mexico. This study was conducted to develop an understanding of the unsaturated hydrologic behavior below the canyon floor. The main goal of this study was to evaluate the hypothetical performance of the vadose zone above the water table. Numerical simulations of unsaturated groundwater flow at the site were conducted using the Finite Element Heat and Mass Transfer (FEHM) code. A two-dimensional cross-section along the canyon's axis was used to model flow between an alluvial groundwater system and the regional aquifer approximately 300 m below. Using recharge estimated from a water budget developed in 1967, the simulations showed waters from the perched water table reaching the regional aquifer in 13.8 years, much faster than previously thought. Additionally, simulations indicate that saturation is occurring in the Guaje pumice bed an d that the Tshirege Unit 1B is near saturation. Lithologic boundaries between the eight materials play an important role in flow and solute transport within the system. Horizontal flow is shown to occur in three thin zones above capillary barriers; however, vertical flow dominates the system. Other simulations were conducted to examine the effects of changing system parameters such as varying recharge inputs, varying the distribution of recharge, and bypassing fast-path fractured basalt of uncertain extent and properties. System sensitivity was also explored by changing model parameters with respect to size and types of grids and domains, and the presence of dipping stratigraphy.
Date: October 15, 1998
Creator: Dander, D.C.
Partner: UNT Libraries Government Documents Department

Transport properties of Topopah Spring tuff

Description: Electrical resistivity, ultrasonic P-waves velocity, and water permeability were measured simultaneously on both intact and fractured Topopah Spring tuff samples at a confining pressure of 5.0 MPa, pore pressures to 2.5 MPa, and temperatures to 140{sup 0}C. The tested samples were subjected to three dehydration and rehydration cycles. The dehydrations were accomplished at a temperature of 140{sup 0}C, and the rehydrations were accomplished at various combinations of temperature and pore pressures so that the wetting fluid was either liquid water, steam or both. The electrical resistivity measurements indicate that for the intact sample, the drying and resaturation took place fairly uniformly throughout the sample. On the other hand, for the fractured sample, the drying and resaturation was spatially quite nonuniform. When samples had been subjected to 5 MPa of confining pressure and 140{sup 0}C for several weeks, a gradual monotonic drift in resistivity was measured (decreasing resistivity when dry; increasing resistivity when wet). This may be the result of either minerological changes or grain boundary movement. In any case, the phenomenon may have important consequences on long term repository performance, and should be studied further. The permeability of the intact sample was independent of temperature, dehydration and rehydration cycles, and time. The permeability of the fractured sample, initially dominated by the fracture, decreased by about one order of magnitude after each dehydration and rehydration cycle. 11 references, 12 figures, 3 tables.
Date: October 1, 1984
Creator: Lin, W. & Daily, W.
Partner: UNT Libraries Government Documents Department

Integrated approach towards the application of horizontal wells to improve waterflooding performance. Quarterly report, January 1--March 31, 1997

Description: The overall purpose of the proposed project is to improve secondary recovery performance of a marginal oil field through the use of an appropriate reservoir management plan. The selection of plan will be based on the detailed reservoir description using an integrated approach. The authors expect that 2 to 5% of the original oil in place will be recovered using this method. This should extend the life of the reservoir by at least 10 years. The project is divided into two stages. In Stage 1 of the project, the authors selected part of the Glenn Pool Field-Self Unit. They conducted cross borehole tomography surveys and formation micro scanner logs through a newly drilled well. By combining the state-of-the-art data with conventional core and log data, they developed a detailed reservoir description based on an integrated approach. After conducting extensive reservoir simulation studies, they evaluated alternate reservoir management strategies to improve the reservoir performance including drilling of a horizontal injection well. They observed that selective completion of many wells followed by an increase in the injection rate was the most feasible option to improve the performance of the Self Unit. This management plan is currently being implemented and the performance is being monitored. Stage 2 of the project will involve selection of part of the same reservoir (Berryhill Unit-Tract 7), development of reservoir description using only conventional data, simulation of flow performance using developed reservoir description, selection of an appropriate reservoir management plan, and implementation of the plan followed by monitoring of reservoir performance.
Date: October 1, 1997
Creator: Kelkar, M.; Liner, C. & Kerr, D.
Partner: UNT Libraries Government Documents Department

Improved Efficiency of Miscible CO{sub 2} Floods and Enhanced Prospects for CO{sub 2} Flooding Heterogeneous Reservoirs

Description: This work will examine three major areas in which CO{sub 2} flooding can be improved: fluid and matrix interactions, conformance control/sweep efficiency, and reservoir simulation for improved oil recovery. The first full quarter of this project has been completed. We began examining synergistic affects of mixed surfactant versus single surfactant systems to enhance the properties of foams used for improving oil recovery in CO{sub 2} floods. The purpose is to reduce the concentration of surfactants or finding less expensive surfactants. Also, we are examining the effect of oil saturation on the development of foam in CO{sub 2}-surfactant solution systems. CO{sub 2} flooding of low permeability, vugular, and fracture reservoirs are another major thrust of this project. Work conducted this quarter involved simulating gravity stable floods using large core samples; results showed excellent recovery in a low permeability vugular core.
Date: October 31, 1997
Creator: Guo, Boyun (Gordon); Schechter, David S.; Tsau, Jyun-Syung; Grigg, Reid B. & Chang, Shih-Hsien (Eric)
Partner: UNT Libraries Government Documents Department

Increasing waterflood reserves in the Wilmington Oil Field through improved reservoir characterization and reservoir management. Quarterly progress report, July 1, 1995--September 30, 1995

Description: The objectives of this quarterly report are to summarize the work conducted under each task during the reporting period July-September 1995, and to report all technical data and findings as specified in the {open_quotes}Federal Assistance Reporting Checklist{close_quotes}, The main objective of this project is the transfer of technologies, methodologies, and findings developed and applied in this project to other operators of Slope and Basin Clastic Reservoirs. This project will study methods to identify sands with high remaining oil saturation and to recomplete existing wells using advanced completion technology. The identification of the sands with high remaining oil saturation will be accomplished by developing a deterministic three dimensional (3-D) geologic model and by using a state of the art reservoir management computer software. The wells identified by the geologic and reservoir engineering work as having the best potential will be logged with a pulsed acoustic cased-hole logging tool. The application of the logging tools will be optimized in the lab by developing a rock-log model. The wells that are shown to have the best oil production potential will be recompleted. The recompletions will be optimized by evaluating short radius and ultra-short radius lateral recompletions.
Date: October 30, 1995
Creator: Sullivan, D.; Clarke, D. & Walker, S.
Partner: UNT Libraries Government Documents Department

Analysis of Breakthrough Profiles Based on Gamma Ray Emission Along Loaded Packed Bed Columns: Comparative Evaluation of Ionsiv IE-911 and Chabazite Zeolite for the Removal of Radiostrontium and Cesium from Groundwater

Description: A gamma counting system has been assembled that can profile the breakthrough fronts of gamma-emitting radioisotopes longitudinally and axially along a loaded column. This profiling technique has been particularly useful in columns studies such as those performed with IONSP IE-911, a crystalline silicotitanate (CST) manufactured by UOP, in which unusually long operating times are required to observe cesium breakthrough in column effluent. The length of the mass transfer zone and extent of column saturation can be detected early in a column study by viewing the relative emission of gamma emitters along I the length of the column. In this study, gamma scans were used to analyze loaded CST and zeolite columns used in the treatment of process wastewater simulant and actual groundwater. Results indicate good run-to-run reproductibility in acquiring the scans. The longitudinal gamma scans for both {sup 90}Sr and {sup 137}Cs conformed with breakthrough results reported on the basis of column effluent activity. Although not obvious from data obtained by monitoring effluent activity, the gamma scans indicated that both cesium and strontium in the saturated zone of the CST column are slowly displaced by the higher levels of groundwater cations and are then resorbed further down the column. This displacement phenomenon identified by gamma scans was verified using data from a zeolite column, in which both the gamma scan and column effluent data exhibited radionuclide displacement by groundwater cations. The gamma emission intensities from the CST column runs are used to quantitate and compare the distribution coefficient and loading capacity of {sup 137}Cs on CST versus zeolite.
Date: October 18, 1999
Creator: Bostick, D.T.; DePaoli, S.M. & Lucero, A.J.
Partner: UNT Libraries Government Documents Department

Seismic Evaluation of Hydorcarbon Saturation in Deep-Water Reservoirs

Description: During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we have moved forward on several fronts, including data acquisition as well as analysis and application. During this quarter we have: (1) Completed our site selection (finally); (2) Measured fluid effects in Troika deep water sand sample; (3) Applied the result to Ursa ''fizz gas'' zone; (4) Compared thin layer property averaging on AVO response; (5) Developed target oriented NMO stretch correction; (6) Examined thin bed effects on A-B crossplots; and (7) Begun incorporating outcrop descriptive models in seismic forward models. Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our hydrocarbon indicators. Reservoirs composed of thin bed effects will broaden the reflection amplitude distribution with incident angle. Normal move out (NMO) stretch corrections based on frequency shifts can be applied to offset this effect. Tuning will also disturb the location of extracted amplitudes on AVO intercept and gradient (A-B) plots. Many deep water reservoirs fall this tuning thickness range. Our goal for the remaining project period is to systematically combine and document these various effects for use in deep water exploration.
Date: October 31, 2005
Creator: Batzle, Michael; Han, D-h; Gibson, R. & James, Huw
Partner: UNT Libraries Government Documents Department


Description: The wettability of Berea and chalk samples for gas-oil and gas-water fluids were altered from strong liquid-wetting to intermediate gas-wetting. Two polymers, FC-722 and FC-759, were used to alter the wettability. FC-759 is soluble in water and some 20 times less expensive than FC-722. Gas and liquid relative permeabilities were measured before and after wettability alteration. The results demonstrate a significant increase in liquid-phase relative permeability. Gas-phase relative permeability for a fixed saturation may increase or decrease. However, because of the very high liquid mobility and reduced liquid saturation, the gas mobility also increases for a fixed pressure drop. A number of liquid injectivity tests were also carried out. The results reveal that the liquid-phase mobility can increase significantly when the wettability of rocks is altered from strong liquid-wetting to intermediate gas-wetting. All the results show clearly that the application of wettability alteration to intermediate gas-wetting may significantly increase deliverability in gas condensate reservoirs.
Date: October 15, 2001
Creator: Firoozabadi, Abbas
Partner: UNT Libraries Government Documents Department


Description: OAK-B135 The temperatures of components of DIII-D ECH launchers were observed during 2003 tokamak operation. The injected power was typically 500-700 kW and the pulse length was typically 2s. Plasma shots were performed at intervals of about 17 min from 9 a.m. to 5 p.m. The temperatures of a movable mirror, a fixed mirror and a launcher reached an equilibrium after about six hours of repetitive pulsing. The saturation temperature depends to some extent on the plasma stored energy. However, even in high {beta} plasma, the temperatures plateaued at acceptable values.
Date: October 1, 2003
Partner: UNT Libraries Government Documents Department

Multiscale Thermohydrologic Model

Description: The purpose of the multiscale thermohydrologic model (MSTHM) is to predict the possible range of thermal-hydrologic conditions, resulting from uncertainty and variability, in the repository emplacement drifts, including the invert, and in the adjoining host rock for the repository at Yucca Mountain. Thus, the goal is to predict the range of possible thermal-hydrologic conditions across the repository; this is quite different from predicting a single expected thermal-hydrologic response. The MSTHM calculates the following thermal-hydrologic parameters: temperature, relative humidity, liquid-phase saturation, evaporation rate, air-mass fraction, gas-phase pressure, capillary pressure, and liquid- and gas-phase fluxes (Table 1-1). These thermal-hydrologic parameters are required to support ''Total System Performance Assessment (TSPA) Model/Analysis for the License Application'' (BSC 2004 [DIRS 168504]). The thermal-hydrologic parameters are determined as a function of position along each of the emplacement drifts and as a function of waste package type. These parameters are determined at various reference locations within the emplacement drifts, including the waste package and drip-shield surfaces and in the invert. The parameters are also determined at various defined locations in the adjoining host rock. The MSTHM uses data obtained from the data tracking numbers (DTNs) listed in Table 4.1-1. The majority of those DTNs were generated from the following analyses and model reports: (1) ''UZ Flow Model and Submodels'' (BSC 2004 [DIRS 169861]); (2) ''Development of Numerical Grids for UZ Flow and Transport Modeling'' (BSC 2004); (3) ''Calibrated Properties Model'' (BSC 2004 [DIRS 169857]); (4) ''Thermal Conductivity of the Potential Repository Horizon'' (BSC 2004 [DIRS 169854]); (5) ''Thermal Conductivity of the Non-Repository Lithostratigraphic Layers'' (BSC 2004 [DIRS 170033]); (6) ''Ventilation Model and Analysis Report'' (BSC 2004 [DIRS 169862]); (7) ''Heat Capacity Analysis Report'' (BSC 2004 [DIRS 170003]).
Date: October 12, 2004
Creator: Buscheck, T.
Partner: UNT Libraries Government Documents Department


Description: In this report we will show the fundamental concepts of two different methods to compute seismic energy absorption. The first methods gives and absolute value of Q and is based on computation with minimum phase operators. The second method gives a relative energy loss compared to a background trend. This method is a rapid, qualitative indicator of anomalous absorption and can be combined with other attributes such as band limited acoustic impedance to indicate areas of likely gas saturation.
Date: October 1, 2003
Creator: Walls, Joel; Taner, M.T.; Derzhi, Naum; Mavko, Gary & Dvorkin, Jack
Partner: UNT Libraries Government Documents Department

Modeling seepage into heated waste emplacement tunnels in unsaturated fractured rock

Description: Predicting the amount of water that may seep into waste emplacement tunnels (drifts) is important for assessing the performance of the proposed geologic repository for high-level radioactive waste at Yucca Mountain, Nevada. The repository will be located in thick, partially saturated fractured tuff that-for the first several hundred years after emplacement-will be heated to above-boiling temperatures as a result of heat generation from the decay of radioactive waste. Heating of rock water to above-boiling conditions induces water saturation changes and perturbs water fluxes that affect the potential for water seepage into drifts. In this paper, we describe numerical analyses of the coupled thermal-hydrological (TH) processes in the vicinity of waste emplacement drifts, evaluate the potential of seepage during the heating phase of the repository, and discuss the implications for the performance of the site. In addition to the capillary barrier at the rock-drift interface-independent of the thermal conditions-a second barrier exists to downward percolation at above-boiling conditions. This barrier is caused by vaporization of water in the fractured rock overlying the repository. A TOUGH2 dual-permeability simulation model was developed to analyze the combined effect of these two barriers; it accounts for all relevant TH processes in response to heating, while incorporating the capillary barrier condition at the drift wall. Model results are presented for a variety of simulation cases that cover the expected variability and uncertainty of relevant rock properties and boundary conditions.
Date: October 1, 2003
Creator: Birkholzer, Jens T.; Mukhopihadhyay, Sumit & Tsang, Yvonne W.
Partner: UNT Libraries Government Documents Department


Description: The objective of this project is to increase oil recovery from fractured reservoirs through improved fundamental understanding of the process of spontaneous imbibition by which oil is displaced from the rock matrix into the fractures. Spontaneous imbibition is fundamentally dependent on the reservoir surface free energy but this has never been investigated for rocks. In this project, the surface free energy of rocks will be determined by using liquids that can be solidified within the rock pore space at selected saturations. Thin sections of the rock then provide a two-dimensional view of the rock minerals and the occupant phases. Saturations and oil/rock, water/rock, and oil/water surface areas will be determined by advanced petrographic analysis and the surface free energy which drives spontaneous imbibition will be determined as a function of increase in wetting phase saturation. The inherent loss in surface free energy resulting from capillary instabilities at the microscopic (pore level) scale will be distinguished from the decrease in surface free energy that drives spontaneous imbibition. A mathematical network/numerical model will be developed and tested against experimental results of recovery versus time over broad variation of key factors such as rock properties, fluid phase viscosities, sample size, shape and boundary conditions. Two fundamentally important, but not previously considered, parameters of spontaneous imbibition, the capillary pressure acting to oppose production of oil at the outflow face and the pressure in the nonwetting phase at the no-flow boundary versus time, will also be measured and modeled. Simulation and network models will also be tested against special case solutions provided by analytic models. In the second stage of the project, application of the fundamental concepts developed in the first stage of the project will be demonstrated. The fundamental ideas, measurements, and analytic/numerical modeling will be applied to mixed-wet rocks. Imbibition measurements will include ...
Date: October 1, 2004
Creator: Morrow, Norman R.; Fischer, Herbert; Li, Yu; Mason, Geoffrey; Ruth, Douglas; Seth, Siddhartha et al.
Partner: UNT Libraries Government Documents Department

Electromagnetic Weibel Instability in Intense Charged Particle Beams with Large Energy Anisotropy

Description: In plasmas with strongly anisotropic distribution functions, collective instabilities may develop if there is sufficient coupling between the transverse and longitudinal degrees of freedom. Our previous numerical and theoretical studies of intense charged particle beams with large temperature anisotropy [E. A. Startsev, R. C. Davidson and H. Qin, PRSTAB, 6, 084401 (2003); Phys. Plasmas 9, 3138 (2002)] demonstrated that a fast, electrostatic, Harris-like instability develops, and saturates nonlinearly, for sufficiently large temperature anisotropy (T{sub {perpendicular}b}/T{sub {parallel}b} >> 1). The total distribution function after saturation, however, is still far from equipartitioned. In this paper the linearized Vlasov-Maxwell equations are used to investigate detailed properties of the transverse electromagnetic Weibel-type instability for a long charge bunch propagating through a cylindrical pipe of radius r{sub w}. The kinetic stability analysis is carried out for azimuthally symmetric perturbations about a two-temperature thermal equilibrium distribution in the smooth-focusing approximation. The most unstable modes are identified, and their eigenfrequencies, radial mode structure and instability thresholds are determined. The stability analysis shows that, although there is free energy available to drive the electromagnetic Weibel instability, the finite transverse geometry of the charged particle beam introduces a large threshold value for the temperature anisotropy ((T{sub {perpendicular}b}/T{sub {parallel}b}){sup Weibel} >> (T{sub {perpendicular}b}/T{sub {parallel}b}){sup Harris}) below which the instability is absent. Hence, unlike the case of an electrically neutral plasma, the Weibel instability is not expected to play as significant a role in the process of energy isotropization of intense unneutralized charged particle beams as the electrostatic Harris-type instability.
Date: October 20, 2003
Creator: Startsev, Edward A. & Davidson, Ronald C.
Partner: UNT Libraries Government Documents Department

Advanced Liquid Natural Gas Onboard Storage System

Description: Cummins Westport Incorporated (CWI) has designed and developed a liquefied natural gas (LNG) vehicle fuel system that includes a reciprocating pump with the cold end submerged in LNG contained in a vacuum-jacketed tank. This system was tested and analyzed under the U.S. Department of Energy (DOE) Advanced LNG Onboard Storage System (ALOSS) program. The pumped LNG fuel system developed by CWI and tested under the ALOSS program is a high-pressure system designed for application on Class 8 trucks powered by CWI's ISX G engine, which employs high-pressure direct injection (HPDI) technology. A general ALOSS program objective was to demonstrate the feasibility and advantages of a pumped LNG fuel system relative to on-vehicle fuel systems that require the LNG to be ''conditioned'' to saturation pressures that exceeds the engine fuel pressure requirements. These advantages include the capability to store more fuel mass in given-size vehicle and station tanks, and simpler lower-cost LNG refueling stations that do not require conditioning equipment. Pumped LNG vehicle fuel systems are an alternative to conditioned LNG systems for spark-ignition natural gas and port-injection dual-fuel engines (which typically require about 100 psi), and they are required for HPDI engines (which require over 3,000 psi). The ALOSS program demonstrated the feasibility of a pumped LNG vehicle fuel system and the advantages of this design relative to systems that require conditioning the LNG to a saturation pressure exceeding the engine fuel pressure requirement. LNG tanks mounted on test carts and the CWI engineering truck were repeatedly filled with LNG saturated at 20 to 30 psig. More fuel mass was stored in the vehicle tanks as well as the station tank, and no conditioning equipment was required at the fueling station. The ALOSS program also demonstrated the general viability and specific performance of the CWI pumped LNG fuel system design. ...
Date: October 31, 2003
Creator: Harper, Greg & Powars, Charles
Partner: UNT Libraries Government Documents Department

Well log evaluation of natural gas hydrates

Description: Gas hydrates are crystalline substances composed of water and gas, in which a solid-water-lattice accommodates gas molecules in a cage-like structure. Gas hydrates are globally widespread in permafrost regions and beneath the sea in sediment of outer continental margins. While methane, propane, and other gases can be included in the clathrate structure, methane hydrates appear to be the most common in nature. The amount of methane sequestered in gas hydrates is probably enormous, but estimates are speculative and range over three orders of magnitude from about 100,000 to 270,000,000 trillion cubic feet. The amount of gas in the hydrate reservoirs of the world greedy exceeds the volume of known conventional gas reserves. Gas hydrates also represent a significant drilling and production hazard. A fundamental question linking gas hydrate resource and hazard issues is: What is the volume of gas hydrates and included gas within a given gas hydrate occurrence Most published gas hydrate resource estimates have, of necessity, been made by broad extrapolation of only general knowledge of local geologic conditions. Gas volumes that may be attributed to gas hydrates are dependent on a number of reservoir parameters, including the areal extent ofthe gas-hydrate occurrence, reservoir thickness, hydrate number, reservoir porosity, and the degree of gas-hydrate saturation. Two of the most difficult reservoir parameters to determine are porosity and degreeof gas hydrate saturation. Well logs often serve as a source of porosity and hydrocarbon saturation data; however, well-log calculations within gas-hydrate-bearing intervals are subject to error. The primary reason for this difficulty is the lack of quantitative laboratory and field studies. The primary purpose of this paper is to review the response of well logs to the presence of gas hydrates.
Date: October 1, 1992
Creator: Collett, T.S.
Partner: UNT Libraries Government Documents Department

Effect of reservior heterogeneities on waterflood and EOR chemical flood performance

Description: Simulations were performed to study the capability of a modified version of the black oil simulator BOAST to handle reservoir heterogeneities of the type encountered in the barrier bar depositional system studied in the geoscience research program being performed for the Department of Energy as project BE1. The cases studied consisted of two-dimensional and three-dimensional simulations of layered reservoirs with different permeability contracts between the layers, different vertical permeability/horizontal permeability ratios and continuous and discontinuous shale layers. Software was developed to show graphically the residual oil saturation in the reservoir grid blocks at selected time intervals during the simulation. BOAST was modified for the residual oil saturation displays as well as for graphical displays of production rates and cumulative production versus time of oil, water and gas. 40 refs., 32 figs., 9 tabs.
Date: October 1, 1988
Creator: Tomutsa, L. & Knight, J.
Partner: UNT Libraries Government Documents Department